Vaccines & Immunotherapy Flashcards

1
Q

What would make an ideal vaccine?

A

safe, protective, gives sustained protection, induce neutralizing antibodies, induce protective T cells, low cost, and biologically stable

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2
Q

Types of vaccines

A

subunit
inactivated whole organism
Live
Recombinant

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3
Q

Types of subunit vaccines

A
  • Single protein: toxoid or expression of recombinant DNA in bacteria or yeast
  • Capsular polysaccharide: creates a T-cell independent response – purified polysaccharide and conjugated with non-specific protein to make the response T-cell dependent
  • mRNA
  • DNA
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4
Q

What is a recombinant virus vaccine?

A

benign virus expresses antigen of interest

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5
Q

What are protein component vaccines?

A
  • purified subunit from pathogen or from an engineered organism
  • induces antibody response
  • toxoid
  • viral glycoprotein induces antibodies that bind viral surface to block entry into cells
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6
Q

What is a toxoid?

A
  • inactivated bacterial exotoxin

- lost toxicity but retain antigenicity

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7
Q

Describe polysaccharide vaccines

A
  • need to opsonize via anti-polysaccharide antibodies in order to gain immunity
  • conjugated to toxoid
  • BCR will engulf polysaccharide and present protein antigens on MHC II
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8
Q

Disadvantages of T cell independent antigens

A
  • no isotype switching (can’t change from IgM to IgG for opsonization)
  • no affinity maturation
  • no memory cells
  • insufficient opsonization (only C3b is contributing)
  • children under 2 can’t mount these responses effectively
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9
Q

Describe RNA vaccines

A
  • produced by in vitro transcription of DNA template
  • need to package RNA-dependent RNA-polymerase
  • get into cells with cationic nanoproteins (liposomes) or transfection to hide the RNA
  • rapid mass production
  • involvement of cellular immunity
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10
Q

Describe DNA vaccines

A
  • more stable than RNA

- risk of integrating into host chromosome

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11
Q

Describe inactivated vaccines

A

-quick and safe
-elicit antibody responses
-don’t infect cells; no MCH I presentation
(influenza, polio, etc)

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12
Q

Describe pros and cons of live vaccines

A
  • retain immunogenicity
  • can infect cells and replicate intracellularly (induce CTL and antibody responses)
  • may cause opportunistic infections in immunodeficient patients
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13
Q

What are the 2 types of live vaccines?

A

1) non-virulent viruses in humans but cross protect related human virus
- ex) using cow pox to defend against small pox
2) attenuated microbes that cannot cause disease in healthy patients
- culture in lab or genetically engineer
- ex) polio, measles, mumps, rubella, etc

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14
Q

What is the viral vector of recombinant viral vaccines?

A

engineered virus

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15
Q

Example of a recombinant vaccine

A

Ebola vaccine (rVSV-ZEBOV)

  • live VSV is vector
  • glycoprotein is replaced with Ebola’s glycoprotein
  • cellular and humoral immunity attained
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16
Q

Define adjuvant

A
  • substance that enhances the immunogenicity of antigen
  • promotes accumulation of APCs thru microbial components (producing B7 and IL-12)
  • enhances T and B cell activation
  • can convert soluble proteins into particulate matter to be phagocytized
17
Q

Define immunogen

A

antigen that can ilicit an immune response

18
Q

What are the routes of vaccines?

A
  • most by injection

- live vaccines can be given by nasal spray (influenza) or ingestion (rotavirus, polio)

19
Q

What does a booster shot do?

A

Triggers memory response

20
Q

Define immunotherapy

A

treatment of a disease with therapeutic agents that promote or inhibit immune responses

21
Q

What are the 4 types of immunotherapy?

A

1) antibody therapy
2) cytokine therapy
3) soluble receptor therapy
4) cancer immunotherapy

22
Q

What is an antibody therapy?

A
  • passive immunization
  • provide antiserum or purified antibodies
  • provides immediate, bt temporary protection to patient
  • polyclonal response
  • IgG purified from serum
  • potential of causing a Type III hypersensitivity
23
Q

What is a B cell hybridoma?

A

-cell line derived from the fusion of a single normal B cell with an immortal malignant B cell

24
Q

What are some problems of using monoclonal antibodies?

A
  • mouse Abs have mouse Fcs which cannot opsonize
  • doesn’t always bind human complement or human Fc receptors
  • produce anti-mouse Ig antibodies which is Type III hypersensitivity and neutralize the effects
25
Q

How can we get around monoclonal antibody issues?

A
  • chimeric Abs (30% mouse/70% human sequences): use mouse V region and human C region then cloned into mammalian cells
  • humanized Abs (10% mouse/90% human): use mouse CDR sequences then clone into mammalian sequences
  • human Abs (100% human): developed and produced in lab
26
Q

Describe cytokine therapy

A
  • improve immunity with stimulatory or growth factor cytokines
  • recombinant cytokines: cytokine genes in cell lines allowing for mass production
27
Q

What are some problems with cytokine therapy?

A
  • pleiotrophic effects
  • expensive
  • short half-life meaning frequent administration
28
Q

Describe soluble receptor therapy

A
  • modulate immune responses
  • recombinant soluble receptors: extracellular ligand-binding domain of a receptor fused to Fc portion of human IgG (Ig fusion proteins)
    • easier purification, improved solubility, improved stability, mass production
29
Q

Examples of soluble receptor therapy

A

TNFR-Ig
-binds tightly to soluble TNF
-blocks TNF from binding
-inhibits inflammation
-used for automimmune/inflammatory conditions
CTLA-4-Ig
-binds tightly to B7 – blocks binding to CD28
-no activation of naive T cells
-used for autoimmune diseases and organ transplants